Evaluation of Multiple Herbicides for Control of Sponge Plant (Limnobium laevigatum)

Ben E Willis,Scott W Shuler,Mark A Heilman,West M Bishop

doi:10.4236/gep.2018.66004

Abstract

Sponge plant is an emerging threat that has spread throughout California including the Sacramento-San Joaquin Delta, which is an important water resource for agriculture as well as critical habitat for a variety of threatened and endangered species. More data are needed on effective control methods for this spreading invader, as current management practices are not preventing proliferation. The overall objectives of this research were to evaluate imazamox, penoxsulam, topramezone, florpyrauxifen-benzyl, and carfentrazone-ethyl for control of sponge plant using three testing scales, as well as compare image analysis software to traditional biomass response for measuring herbicide performance. Overall, 280 g imazamox ha?1 (with one-percent methylated seed oil surfactant) was found as a potent solution for all different growth stages of sponge plant, and 70 g penoxsulam ha?1 as an alternative for control of sponge plant in the seedling and rosette growth stage. The image analysis software yielded similar measurement of herbicide effects as traditional biomass measure. Mesocosm testing indicated imazamox treatment sites should be inspected at four week intervals to identify plants missed by prior applications. This research provides water resource managers critical information for identification of an aquatic invasive species, and selecting an effective rapid management program.

Highlights

IntroductionOne such aquatic weed of growing prevalence in California is sponge plant [Limnobium laevigatum (Humboldt and Bonpland ex Willdenow) Heine]
Sponge plant is an emerging threat that has spread throughout California including the Sacramento-San Joaquin Delta, which is an important water resource for agriculture as well as critical habitat for a variety of threatened and endangered species
New invasive weeds are constantly introduced to waterways, which can lead to major ecological changes and economic impact if not appropriately managed

Summary

Introduction

One such aquatic weed of growing prevalence in California is sponge plant [Limnobium laevigatum (Humboldt and Bonpland ex Willdenow) Heine]. This new arrival to the United States is native to South America, Central America, and the Caribbean [1] [2]. This monocot has been found throughout California, though was first documented on 1996 in an East Bay hills pond system [3]. The delta serves as a source of irrigation water for over 200,000 hectares of agricultural land, assists in water conveyance as part of the Central Valley Project and State Water Projects of California, allows navigation for commercial shipping, and has extensive recreational uses [5]

Objectives

Methods

Conclusion